Heretofore a number of additive concentrates containing, inter alia, sulfur-containing antiwear and/or extreme pressure additives, phosphorus-containing antiwear and/or extreme pressure additives, and other additive components have been proposed and used. Among such other additive components are acidic components such as carboxylic acids, hydrocarbyl phosphoric acids, and hydrocarbyl thiophosphoric acids; basic components such as amines; and ashless dispersants such as boronated succinimides.
Many such additive concentrates as supplied are highly acidic in character, exhibiting pH values (as determined by the method described hereinafter) in the range of about 4.0 to about 5.5. Such acidity arises by virtue of use in the concentrates of acidic additives to control wear and corrosion.